1. Field of the Invention
This invention relates to a capacitor-compensation-type generator and a method for controlling the same.
2. Description of the Related Art
There is known a capacitor-compensation-type generator having a rotor wound with a field winding that is short-circuited with a diode, a stator wound with an output winding that is adapted to cross the flux generated by the field winding to produce AC power and with an exciting winding that is disposed at predetermined phase angle with respect to the output winding and is short-circuited with a phase advance capacitor, and an internal combustion engine for driving the rotor relative to the stator, as taught, for example, in Japanese Laid-Open Patent Application No. Sho 63 (1988)-227960. The generator of this type is originally a brushless single-phase synchronous generator that is also called “Nonaka-type generator”, named after the inventor thereof.
In this type of generator, current (whose phase is advanced by 90 degrees by the phase advance capacitor) flows through the exciting winding, field current (which is produced in the field winding by armature reaction) is rectified by the diode, and rotating field is produced by DC magnetizing the rotor (field), which is rotated by the engine, to the N-pole and S-pole. The output winding wound around the stator crosses the flux generated from the rotating field of the rotor, thereby producing AC power.
Since the capacitor-compensation-type generator does not require a brush, slip ring etc., and achieves simple structure, it causes wide spread in the low-price range. However, the output voltage increases with increasing speed of the engine and fluctuates in response to increase or decrease in load, disadvantageously resulting in unstable output voltage. Also, it is preferable for a certain load that frequency is constant, but this type of generator is not necessarily satisfactory in this regard.